Lubricant composition and method



United States Patent O 3,392,117 LUBRICANT COMPOSITION AND METHOD Cecil W. Glasson, Huntington Woods, Mich, assignor to Hooker Chemical Corporation, Niagara Falls, N.Y., a corporation of New York No Drawing. Continuation-impart of application Ser. No. 438,384, Mar. 9, 1965. This application May 2, 1966, Ser. No. 546,604 The portion of the term of the patent subsequent to Apr. 11, 1984, has been disclaimed 7 Claims. (Cl. 252-17) This application is a continuation-in-part of copending application Ser. No. 438,384, filed Mar. 9, 1965, now abandoned.

This invention relates to an improved lubricant composition and more particularly it relates to an improved soap-type lubricant which is useful in lubricating metal surfaces prior to deformation.

In the art of the cold forming of metal, for example metal deformation or metal drawing, it is customary to provide a lubricant coating on the metal surface to be deformed. Heretofore, many substances have been used to provide the desired lubrication of the metal surface during the deforming operation, such as oils, waxes, soaps, and the like. Of these, the most frequently used, at least in recent years, has been a soap-type lubricant, such as a lubricant containing a soap of a fatty acid. Such a lubricant generally has been applied to the metal surface to be deformed as a hot aqueous soap solution. In some instances, and particularly where a difi'icult drawing or deforming operation is involved, before the application of the soap-type lubricant, it is customary to provide a chemical coating on the metal surface to be deformed. Typical of such chemical coatings are phosphate coatings, oxide coatings, oxalate coatings, sulfide coatings, and the like. In both instances, i.e., the application of the lubricant over bare metal or over a chemical coating, the lubricant crushes to a continuous, unctuous film, upon the application of pressure to the metal surface, which continuous film has been found to provide an excellent parting layer between the metal and the die during the deforming operation.

Normally, lubricants of the above type are applied so as to provide a lubricant coating weight on the metal surface of about 100 to 200 milligrams per square foot. In some instances, however, as for example where a particularly severe deforming operation is involved, it has been found that a heavier lubricant coating may be desirable such as one of about 200 to 500 milligrams per square foot. In applying the soap-type lubricants to obtain these higher coating weights, difiiculties have sometimes been encountered in obtaining a substantially smooth and even lubricant coat. Moreover, in such instances, a nonuniform flow of the lubricant has also been experienced, as well as lubricant refiow which results in the formation of lubricant ridges on the coated metal surface. Because of these difficulties, it has generally not been commercially practical to obtain these higher lubricant coating weights when using the soap-type lubricant as has been described hereinabove.

It is, therefore, an object of the present invention to provide a novel soap-type lubricant composition which is useful in metal deforming operations.

Another object of the present invention is to provide a novel soap-type lubricant composition, which composition may be applied with substantially uniform fiow to obtain a substantially even, thicker and heavier lubricant coating than has been possible with prior lubricants.

A further object of the present invention is to provide an improved process for the deformation of metal sur- 3,392,117 Patented July 9, 1968 faces, which process utilizes the improved soap-type lubricant composition of the present invention.

Pursuant to the above objects, the present invention includes a lubricant composition concentrate of the soaptype, which composition comprises a soap of a fatty acid, wherein at least 0.2 percent by weight of the composition but less than about by weight of the soap present in the lubricant composition is a fatty acid soap selected from the group consisting of fatty acid soaps of lithium, potassium, ammonia, zinc, aluminum, calcium, and magnesium and wherein at least 50% of the fatty acid soap is other than a stearic acid soap. Such lubricant compositions have been found to give excellent results in metal deforming operations when applied either directly to the bare metal surface to be deformed or when applied over a chemical coating on the metal surface, such as a phosphate coating, an oxide coating, an oxalate coating, a sulfide coating, or the like.

More specifically, the improved lubricant concentrate compositions of the present invention are comprised of a fatty acid soap wherein at least 5 0% of the fatty acid soap is other than a stearic acid soap and preferably wherein at least of the fatty acid soap is other than a stearic acid soap. Additionally, as has been indicated hereinabove, at least 0.2% by weight of the lubricant concentrate composition but less than about 50% by weight of the soap present in the lubricant composition is a fatty acid soap selected from the group consisting of fatty acid soaps of lithium, potassium, ammonia, calcium, magnesium, zinc and aluminum.

It is to be appreciated that in referring to the present composition as containing a soap, it is intended to include both those compositions which contain the soap, per se, as well as those compositions which contain ingredients which react to form the soap in situ in the composition, such as those compositions containing a fatty acid, or a fat, or an oil and an alkaline material such as a metallic hydroxide or metallic carbonate. Typical of the fatty acid soap used or formed in situ are those containing about 8 to about 22 carbon atoms, with those containing about 12 to about 18 carbon atoms being preferred. Typical of the metallic hydroxides or carbonates used, when the soap is formed in situ, are the hydroxides and carbonates of sodium, potassium, lithium, ammonia, calcium, magnesium, zinc and aluminum.

Generally, it has been found to be desirable that the fatty acid soap selected from the group consisting of fatty acid soaps of lithium, potassium, ammonia, calcium, magnesium, zinc, and aluminum is present in the composition in an amount within the range of about 0.5 to about 15% by weight of the lubricant composition and preferably in an amount within the range of about 0.8 to about 10% by Weight. It will be appreciated, however, that amounts of the fatty acid soap selected from the indicated group in excess of 15% may be used if desired, for example, amounts as high as 30 percent by weight of the lubricant composition. Even greater amounts may be used in some instances. In general, however, it has been found to be desirable if these larger amounts of the selected fatty acid soap are not used and that the major amount of the fatty acid soap in the composition is a fatty acid soap of sodium.

Similarly, with regard to the fatty acid used, substantially 100 percent of the composition may be a fatty acid soap other than a stearic acid soap. Generally, however, it is desirable if at least some stearic acid soap is used in the composition. Thus, in its most preferred embodiment, the lubricant concentrate composition of the present invention contains a sodium tallow soap in an amount within the range of about to about 99% by weight of the lubricant composition and a stearic acid soap selected from the group consisting of stearic acid soaps of lithium, potassium, ammonia, calcium, magnesium, zinc and aluminum in an amount within the range of about 0.8 to about by weight of the lubricant composition.

In addition to the fatty acid soap, the composition of the present invention may also contain various other adjuvants, depending upon the particular characteristics of lubricant compositions which are desired in each instance. For example, rosin and/ or various rosin soaps as well as corrosion inhibitors, dyes, perfumes, and the like, may also be present in the lubricant composition.

The rosin acids which are suitable for inclusion in the present lubricant composition may be in the form of commercial gum or wood rosin, tall oil, or may be extracted from tall oil residues. Accordingly, as used in the specification and claims, the term rosin acid is intended in its generally understood sense and may also include such specific acids as abietic acid, neo-abietic acid, pimaric acid, levo-pimaric acid, dextro-pimaric acid, isodextro-pimaric acid, mixtures thereof, and the like, and the rosin soaps are soaps made from these acids. Where rosin soaps and/or rosin acids are included in the lubricating composition, they are typically present in amounts within the range of about 0.1% to about by weight of the lubricant composition and preferably are present in amounts within the range of about 0.5 to about 10%.

Corrosion inhibiting materials which may be included in the lubricating compositions are exemplified by the alkali metal nitrates, the alkali metal nitrates and the like. These and other inhibitors, as are known to those in the art, when used, are typically present in amounts within the range of about 0.1% to about 5.0% by weight of the lubricant composition, and are preferably present in amounts within the range of about 0.1% to about 3.0%. Dyes, such as bismarck brown, and the like, and perfumes or other materials for imparting a pleasant odor to the composition, such as pine oil and the like, may also be incorporated in the composition in amounts sufiicient to impart the desired color and odor to the composition. It is to be appreciated that the term alkali metal as used in the specification and claims is intended to refer to sodium, lithium, potassium, cesium, and rubidium. Generally, hereinafter reference will be made to the compounds of sodium as being the preferred alkali metal but this is not to be taken as a limitation of the invention but merely as being exemplary thereof.

In addition to the above adjuvants, the lubricant concentrate composition of the present invention may also contain water, the amount depending upon the physical form which is desired for the concentrate composition. Typically, water in amounts up to about 80 percent by weight of the lubricant concentrate composition may be used, with amounts within the range of about 15 to about 75 percent by weight of the lubricant composition being preferred. It will be appreciated by those in the art, in determining the physical form or consistency of the lubricant concentrate composition which is desired, consideration will, of course, be given to manner in which the composition is to be handled, packaged and transported. Accordingly, the amount of water included in the lubricant concentrate composition may vary widely, and in some instances may even exceed 80% by weight.

Even when water in an amount of about 75% by weight of the lubricant composition is used, the composition may still be sufliciently concentrated as to be undesirable for many applications to metallic surfaces. Accordingly, in formulating a working composition for application to a metal surface, the concentrated lubricant composition will generally be further diluted with water. Typical working compositions may contain the lubricant concentrate in amounts within the range of about 10 to about 400 pounds per hundred gallons of solution. Generally, where a heavier lubricant coating is desired 4 on the metal surface, such as a coating of at least 200 milligrams per square foot, it has been found to be desirable to use a more concentrated lubricant composition such as those containing at least about 125 pounds of the lubricant concenrate per hundred gallons of solution.

The aqueous working lubricant composition, containing the lubricant concentrate within the range of about 10 to about 400 pounds per hundred gallons of solution will have a Babcock number within the range of about 0.1 to about 15.2 and a titration number within the range of about 3.0 to about 80.0. The Babcock number is obtained by the following procedure: A 100 milliliter Cassia flask is provided with a 50 milliliter sample of the working solution and to this sample, 30 milliliters of 50 percent sulfuric acid is added and thoroughly admixed. The flask is then placed in a hot water bath having a temperature between about 82 centigrade and boiling. The level of the water should be high enough to cover most of the neck of the Cassia flask. After about 15 to 30 minutes, sufiicient hot, boiled water is added to bring the oily layer into graduated neck of the flask. When the oily layer has separated sharply, usually in about 5 minutes, the difference between the reading of the lower and upper edges of the oily column in the neck is the Babcock numbet. The titration number is obtained by the following procedure: 50 milliliters of the hot lubricant solution at degrees centigrade is put into a beaker with about 120 milliliters of hot water. This solution is then titrated with 0.88 N sulfuric acid. The titration number is the number of milliliters of the sulfuric acid needed to titrate the lubricant solution to the bromocresol green end point.

The working lubricant solutions, as described above, may be applied to the metal surfaces to be deformed in various ways, such as by immersion, flow coating, by spraying, or by roller application. For such applications the lubricant temperature may be widely varied, from about room temperature, i.e., about 20 degrees centigrade, up to about degrees centigrade. Generally, for application by immersion techniques, higher temperatures of the lubricant composition are desired, such as temperatures of about 60 to 100 degrees centigrade. For roller applications lower temperatures such as from room temperature up to about 60 degrees centigrade may be used. It has been found that in the latter instance, i.e., the roller application of the lubricant composition at room temperature, it may be desirable to use the lubricant composition as a concentrate with no further dilution, applying the concentrated composition to the roll with air pressure, a reciprocating piston pump, a centrifugal pump, or the like. It is believed that the details of the various techniques whereby the lubricant composition of the present invention may be applied are sufficiently familiar to those in the art that further descriptions of such methods are not necessary.

As has been noted hereinabove, the lubricant composition of the present invention is particularly adapted for application to chemically coated metal surfaces, prior to the deformation of the surfaces. Suitable chemical coatings which may be applied to the surfaces prior to the application of the lubricant composition include phosphate coatings, oxide coatings, oxalate coatings, sulfide coating and the like.

In forming metal articles, in accordance with the process of the present invention, the subject lubricant composition is applied to the bare metal surfaces or to a chemically coated metal surface, using application techniques as has been indicated hereinabove, to obtain the desired amount of the lubricant composition on the surface. The lubricant coating thus-obtained isdried, and thereafter, the coated surface is subjected to drawing, cold forming, or other deforming operations. Generally, the application of the chemical coating to the metal surface, such as a phosphate coating, or the application of the lubricant to a bare metal surface, is preceded by a cleaning or pickling step and a rinse to remove the cleaning or pickling solution. Frequently, between the application of the chemical coating and the lubricant coating, the chemically coated surface is also rinsed to remove any unreacted coating material. Although this latter rinse may be a water rinse, alkaline or neutralizing rinses may also be used. It is believed that the composition and nature of the various chemical coating materials and rinses as well as the manner in which they may be applied to the metal surfaces, and the specific details of the various metal deforming operations, such as cold forming and drawing, are all sufficiently well known to those in the art that a further detailed description of these compositions and processes is not necessary.

It has been found that the lubricant composition of the present invention, which contain a fatty acid selected from the group consisting of fatty acids of lithium, potassium, calcium, magnesium, ammonia, zinc and aluminum are characterized by having uniform flow properties when used at higher concentrations, such as those in excess of about 125 pounds of lubricant per hundred gallons of working solution and that further, when used at these concentrations have a low viscosity and provide a substantially uniform, even lubricant coating on the metal surface, even when the coating has a coating weight of at least 200 milligrams per square foot. In contrast, similar lubricant compositions but which do not contain the fatty acid selected from the indicated group, when used at similar high concentrations, have a higher viscosity and do not have the desired uniform flow characteristics and the lubricant coating obtained from their application is frequently uneven. Such unevenness in the lubricant film has been found to be particularly disadvantageous where a difficult or a hard drawing operation is to be effected. This unevenness in lubricant flow is particularly disadvantageous where a polished surface is being deformed, in that after the deforming operation, the ridges in the lubricant coating are found to be reproduced in the deformed surface. Such a phenomenon is known in the art as coining.

In order that those skilled in the art may better understand the present invention and the manner in which it may be practiced, the following specific examples are given. In these examples, unless Otherwise indicated, the temperatures are given in degrees centigrade and the parts are by weight.

Example 1 A lubricant concentrate was made of 770 parts of a sodium tallow soap and parts of aluminum stearate. Water was then admixed with this lubricant concentrate to obtain an aqueous working lubricant solution containing 1.25 pounds of a lubricant concentrate per gallon of solution. This aqueous lubricant solution was maintained at a temperature of about 80 degrees centigrade and bare 4 inch by 6 inch steel panels were immersed therein for 1 minute. The panels were then removed from the lubricant composition and dried at about 120 degrees centigrade. During the application of the lubricant to the panels it was noted that the lubricant had good reflow characteristics. The lubricant film produced had a substantially uniform thickness and showed no evidence of unevenness or ridging. This lubricant film was found to be suitable for protecting the metal to which it was applied during relatively severe drawing operations.

Example 2 ously been coated with a conventional zinc phosphate coating, using the procedure as in Example 1. The reflow characteristics of this lubricant material were found to be very good and the lubricant film produced on the phosphate coated panel was found to be substantially smooth, without ridges and was suitable for protecting the metal during relatively severe drawing operations.

By way of comparison, the procedure of the preceding two examples was repeated with the exception that in each instance, the aluminum stearate and lithium stearate were omitted from the lubricant composition. In both cases during the application of the lubricant, it was noted that the reflow characteristics of the lubricant were poor and the lubricant film produced was quite uneven and showed appreciable ridging.

Example 3 Additional runs were made using the procedure of Example 1 but wherein the following materials were substituted for the aluminum stearate used in the lubricant concentrate of that example: Calcium stearate, zinc stearate, magnesium stearate, potassium stearate, and ammonium stearate. In each instance, an excellent lubricant film was obtained, which film was substantially even and had uniform fiow characteristics.

While there have been described various embodiments of the invention, the compositions and methods described are not intended to be understood as limiting the scope of the invention, as it is realized that changes therewithin are possible and it is further intended that each element recited in any of the following claims is to be understood as referring to all equivalent elements for accomplishing substantially the same result in substantially the same or equivalent manner, it being intended to cover the invention broadly in whatever form its principle may be utilized.

What is claimed is:

1. A lubricant composition useful in lubricating metal surfaces prior to deformation which consists essentially of fatty acid soaps, wherein at least 0.2 percent by weight of the composition but less than about 50 percent by weight of the soap present in the lubricant composition is a fatty acid soap selected from the group consisting of fatty acid soaps of lithium, potassium, ammonia, zinc, aluminum, calcium, and magnesium, the remainder of the fatty acid soap being a fatty acid soap of sodium and wherein at least 50 percent of the fatty acid soap in the composition is a fatty acid soap containing 8-22 carbon atoms, other than a stearic acid soap, the remainder of the fatty acid soap being a stearic acid soap.

2. The lubricant composition as claimed in claim 1 wherein at least 60 percent of the fatty acid soap in the composition is other than a stearic acid soap, the fatty acid soap selected fro-m the group consisting of fatty acid soaps of lithium, potassium, ammonia, calcium, magnesium, zinc and aluminum is present in an amount within the range of about 0.2 to about 30 percent by weight of the lubricant composition, and wherein there is also present in the composition water in an amount up to about percent by weight of the composition.

3. The composition as claimed in claim 2 wherein there is -99 percent by weight of sodium a tallow soap and 0.4-10 percent by weight of a stearic acid soap selected from the group consisting of stearic acid soaps of lithium, potassium, ammonia, calcium, magnesium, zinc and aluminum.

4. A metal surface having deposited thereon, a lubricating amount of the lubricant material as claimed in claim 1.

5. The metal surface as claimed in claim 4 wherein the lubricant material contains the fatty acid soap selected from the indicated group in an amount within the range of about 0.2 to about 30 percent by weight of the composition and wherein at least 60 percent of the fatty acid soap is other than a stearic acid soap.

6. The metal surface as claimed in claim 5 wherein the lubricant coating comprises from 90-99 percent by weight of a sodium tallow soap and from 0.4 to 10 percent by weight of a stearic acid soap selected from the group consisting of stearic acid soaps of lithium, potassium, ammonia, calcium, zinc, magnesium and aluminum.

7. The metal siirface as claimed in claim 6 wherein the 2,840,890 7/1958 Emm 252-9 metal surface is 'achemically coated metal surface. 2,849,107 8/ 1958 Logue 252--49.3

2,963,391 12/1960 Kubie 252-493 References Cited UNITED STATES PATENTS 5 DANIEL E. WYMAN, Primary Examiner.

2,413,220 12/1946 Elder et a1. 252-35 I. VAUGHN, Assistant Examiner. 

1. A LUBRICANT COMPOSITION USEFUL IN LUBRICATING METAL SURFACES PRIOR TO DEFORMATION WHICH CONSISTS ESSENTIALLY OF FATTY ACID SOAPS, WHEREIN AT LEAST 0.2 PERCENT BY WEIGHT OF THE COMPOSITION BUT LESS THAN ABOUT 50 PERCENT BY WEIGHT OF THE SOAP PRESENT IN THE LUBRICANT COMPOSITION IS A FATTY ACID SOAP SELECTED FROM THE GROUP CONSISTING OF FATTY ACID SOAPS OF LITHIUM, POTASSIUM, AMMONIA, ZINC, ALUMINUM, CALCIUM, AND MAGNESIUM, THE REMAINDER OF THE FATTY ACID SOAP BEING A FATTY ACID SOAP OF SODIUM AND WHEREIN AT LEAST 50 PERCENT OF THE FATTY ACID SOAP IN THE COMPOSITIONS IS A FATTY ACID SOAP CONTAINING 8-22 CARBON ATOMS, OTHER THAN A STEARIC ACID SOAP, THE REMAINDER OF THE FATTY ACID SOAP BEING A STEARIC ACID SOAP. 